Many of his clients had entered Britain legally on work permits or student visas and believed he would help them stay in the country through legal means.

But Azad used forged documents including bogus Home Office stamps and letters, as well as fake college stamps, letters and national insurance cards.

Sandip Patel, prosecuting, said those provided with forged documents by Azad 'had access to numerous privileges, state benefits, employment and unfettered continuous residence'.

He said: 'Mr Azad forged Home Office stamps and paperwork and they were thereafter accepted by the authorities as genuine.'

Many of those he helped have now disappeared.

The court heard that one client, Tariq Chaudhry, went to Azad believing him to be a genuine immigration lawyer. He was able to become a naturalised British citizen two years ago using a bogus 'indefinite leave to remain' stamp Azad supplied for him.

Another client paid £3,100 to Azad in 2003 believing he could help him and his Filipino wife stay in the country legally, only to be arrested in an immigration raid.

When the Serious and Organised Crime Agency (SOCA) raided Azad's office in 2007 they found cash, hundreds of passports and files relating to up to 15,000 people.

A SOCA source said: 'Azad's files were grouped under family names, each of which had two or three people in, perhaps more, suggesting he could have helped 15,000 with bogus details, many of whom cannot now be traced and are not known to the Home Office. He has cost the taxpayer millions.'

The court heard that nearly £18,000 in cash was seized by SOCA and workers later testified they had been asked to bank cheques for as much as £37,000.

Azad even posed as former Lord Mayor of Manchester Afzal Khan and wrote to Blackley MP Graham Stringer for help with a case.

After Azad was jailed in 2002 for a similar passport scam, Mr Khan had given him a job helping out with administration and community work.

Mr Khan said: 'He was someone who had enjoyed standing in the community and I gave him some work because I felt sorry for him.

'I thought that after going to prison the first time he would have learnt his lesson, so I feel very saddened by this.'

Mr Stringer said: 'He was as bent as a nine bob note.'

Azad, who has prostate cancer, was given a suspended sentence in 2008 for providing immigration services when not qualified. Bunty Batra, defending, said Azad was a dying man who had started out wanting to help people before becoming greedy.

Sentencing, Judge Roger Thomas QC, said Azad was at the centre of a fake immigration industry, adding that rather than helping people with genuine cases he had, in fact, harmed their cause.

He added: 'This particular form of conduct is becoming prevalent and a message has to go out loud and clear about what happens to those people who misuse the system as you have done.'